1. Field of the Invention PA1 2. Description of the Prior Art
This invention relates in general to storage batteries and to methods of manufacturing storage batteries. In particular, this invention relates to lead storage batteries of the type used in automobiles, and to methods of manufacturing such batteries.
A typical twelve-volt lead storage battery has a battery case divided into six cells. A stack of positive and negative battery plates is located in each cell. The positive plates are typically made of lead dioxide and the negative plates are typically metallic lead. The lead dioxide or metallic lead is usually coated onto a grid of metallic lead. The plates in a stack are separated by treated wood or glass fiber spacers.
Rest ups extend upward from the bottom of the case to support the stacks. The rest ups hold the plates off of the bottom of the case, so that any debris formed on the plates during operation of the battery will fall to the bottom of the battery case below the plates. This helps avoid shorting between the plates.
The battery case is filled with an electrolyte, such as a sulfuric acid solution. The battery plates are highly porous to provide maximum surface area for contact with the electrolyte. The electrolyte reacts with the battery plates to cause an electric charge to pass through the battery.
In order for the electric charge to pass from cell to cell, the positive plates in one cell must be electrically connected to the negative plates in the next cell. In many cases, these connections are made by welding lead connectors between the plates with a burning machine. Another method of connecting the plates is by casting a lead connector directly onto the stacks with a cast-on machine. Both of these methods involve a considerable amount of labor and machinery. The process can be made more economical by removing or reducing the amount of labor and machinery required.
U.S. Pat. No. 4,509,253, issued Apr. 9, 1985, to Eberle, discloses a storage battery and a method of making storage batteries in which the positive plates of one cell are electrically connected to the negative plates of an adjacent cell without the need for welding or casting. A conventional battery case is modified to provide openings through the partitions between the cells. Lugs on the positive plates in each cell are positioned downward and are aligned with lugs on the negative plates in the next cell. A conductive material is added to the bottoms of the cells and extends through the openings between cells to electrically connect the positive lugs in one cell to the negative lugs in the next cell. A sealing agent, such as epoxy resin, may be placed over the conductive material to hold the material in place and to protect the material from the electrolyte in the battery case.
The conductive material is a low temperature lead alloy, that includes bismuth and cadmium. When the batteries are recycled, the cadmium must be removed from the lead alloy. This involves a dangerous and expensive process.